Deep dive at WaPo:
The result of the country’s evolution has been a Senate that suffers from three fundamental imbalances, according to a Washington Post data analysis of population growth, demographic changes and shifts in voting patterns.
First, the disparities in power among voters in different states have widened as states have grown unevenly. Second, because of demographic distribution, White voters now have substantially greater influence than voters of color. And finally, in recent decades, Republican senators have maintained majority control even when they represent a minority of Americans. That’s because more Republicans than Democrats are elected in the least populous states.
Though not the sole reason, these imbalances have contributed to the Senate’s inability to enact legislation that enjoys popular support, from voting rights to gun safety laws. Proposals with widespread support among voters of color have been particularly stymied. The Senate’s distortions are also a factor in perceptions, especially among people on the political left, that the Republican Party and its constituencies enjoy outsize power over essential democratic processes, including the confirmation of Supreme Court justices.
As the country continues to gain population and become more diverse, none of these phenomena appear to be going away.